Freestyle line doesn't show anymore
After blood, sweat and tears I've decide to just copy my mesh and armature by selecting it and pressing ctrl + c and then in another file pressing ctrl + v and the line shows up in the new file just fine. 

I don't know what the problem is in the previous file (I did transfer it via google drive maybe that messed something up?)

Conclusion: If something doesnt render properly try copying your mesh (and armature) to another file